With increasing frequency over the past 25 years, mindfulness has been linked with health and psychological wellbeing. Recently it has also been linked with healthy interpersonal relationships. The present cross-sectional study of 331 diverse adults tested a proposed model for understanding the association between mindfulness and relationship satisfaction through the effects of three concepts related to emotion: emotion regulation, empathy and positivity (ratio of positive to negative affect). Perspective taking, a cognitive aspect of empathy, and positivity partially mediated the association between both mindfulness and relationship satisfaction and mindfulness facet nonreactivity and relationship satisfaction. Positivity emerged as the strongest mediator in both cases. Empathic concern, an affective aspect of empathy, was found to be a significant mediator of the association between mindfulness and relationship satisfaction only in individuals with a mindfulness meditation practice and for those with very high levels of emotional awareness. When empathic concern was tested as a mediator of the association between nonreactivity and relationship satisfaction, it was only significant in individuals with high levels of emotional dysregulation.